Subject: bug#70362: [PATCH] Add font-locking for Go built-in functions in go-ts-mode

From: Noah Peart <[email-masked]>
Date: Fri, 12 Apr 2024 22:47:37 -0700

Tags: patch

This patch adds a new `builtin` feature to
`treesit-font-lock-feature-list` in `go-ts-mode` and a corresponding
rule to `go-ts-mode--font-lock-settings` to highlight Go's built-in
functions.
From feaf5598a5a63867f7dc5bf8f2c11c047b11483f Mon Sep 17 00:00:00 2001
From: Noah Peart <[email-masked]>
Date: Fri, 12 Apr 2024 22:38:28 -0700
Subject: [PATCH] Add font-locking for Go built-in functions in go-ts-mode

* lisp/progmodes/go-ts-mode.el (go-ts-mode--font-lock-settings):
Add font-locking for Go built-in functions to go-ts-mode.
---
 lisp/progmodes/go-ts-mode.el | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/lisp/progmodes/go-ts-mode.el b/lisp/progmodes/go-ts-mode.el
index cc330688dc3..a1736703b62 100644
--- a/lisp/progmodes/go-ts-mode.el
+++ b/lisp/progmodes/go-ts-mode.el
@@ -108,6 +108,11 @@ go-ts-mode--operators
     ">>" "%=" ">>=" "--" "!"  "..."  "&^" "&^=" "~")
   "Go operators for tree-sitter font-locking.")
 
+(defvar go-ts-mode--builtin-functions
+  '("append" "cap" "clear" "close" "complex" "copy" "delete" "imag" "len" "make"
+    "max" "min" "new" "panic" "print" "println" "real" "recover")
+  "Go built-in functions for tree-sitter font-locking.")
+
 (defun go-ts-mode--iota-query-supported-p ()
   "Return t if the iota query is supported by the tree-sitter-go grammar."
   (ignore-errors
@@ -154,6 +159,16 @@ go-ts-mode--font-lock-settings
      (var_spec name: (identifier) @font-lock-variable-name-face
                ("," name: (identifier) @font-lock-variable-name-face)*))
 
+   :language 'go
+   :feature 'builtin
+   `((call_expression
+      function: ((identifier) @font-lock-builtin-face
+                 (:match ,(rx-to-string
+                           `(seq bol
+                                 (or ,@go-ts-mode--builtin-functions)
+                                 eol))
+                         @font-lock-builtin-face))))
+
    :language 'go
    :feature 'function
    '((call_expression
@@ -256,7 +271,7 @@ go-ts-mode
     (setq-local treesit-font-lock-feature-list
                 '(( comment definition)
                   ( keyword string type)
-                  ( constant escape-sequence label number)
+                  ( constant escape-sequence label number builtin)
                   ( bracket delimiter error function operator property variable)))
 
     (treesit-major-mode-setup)))
-- 
2.34.1